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authorPavel Begunkov <asml.silence@gmail.com>2022-09-27 00:44:39 +0100
committerJens Axboe <axboe@kernel.dk>2022-09-26 18:44:15 -0600
commitbf68b5b34311ee57ed40749a1257a30b46127556 (patch)
tree2f99ab4a5d2c2c7f29bfd836573ab44aa87973ae /io_uring
parent4c17a496a7a0730fdfc9e249b83cc58249111532 (diff)
io_uring/rw: fix unexpected link breakage
req->cqe.res is set in io_read() to the amount of bytes left to be done, which is used to figure out whether to fail a read or not. However, io_read() may do another without returning, and we stash the previous value into ->bytes_done but forget to update cqe.res. Then we ask a read to do strictly less than cqe.res but expect the return to be exactly cqe.res. Fix the bug by updating cqe.res for retries. Cc: stable@vger.kernel.org Reported-and-Tested-by: Beld Zhang <beldzhang@gmail.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3a1088440c7be98e5800267af922a67da0ef9f13.1664235732.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/rw.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 59c92a4616b8..ed14322aadb9 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -793,6 +793,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
return -EAGAIN;
}
+ req->cqe.res = iov_iter_count(&s->iter);
/*
* Now retry read with the IOCB_WAITQ parts set in the iocb. If
* we get -EIOCBQUEUED, then we'll get a notification when the